Democrats' Hope: Keeping Zeal For General Election

The hardest thing to come by in politics is genuine enthusiasm. Campaigns can buy ads, and direct mail pieces, and robo-calling phone banks. They can't buy zeal.

Democrats have it right now. You could see it in last week's Super Tuesday primary results, when even in conservative "red" states more people turned out to vote in Democratic primaries than in Republican ones. I could see it this morning in the long lines at the polling place at my daughter's elementary school, which is located in the "blue" Montgomery County Maryland.

What Democrats have to hope is that their enthusiasm survives the strain of a prolonged competition over the next few weeks between Barack Obama and Hillary Clinton.

Potomac Primaries

Voters in the Potomac states head to polls today, with CNBC's John Harwood